- "You will rule all the galaxy as the new Emperor."
- ―Darth Sidious, to Kylo Ren
Emperor (feminine Empress) was the title of a leader who wielded autocratic power over an Empire. Millennia before the fall of the Galactic Republic, the blue-skinned Anselmi formed their own empire on Glee Anselm, ruled by an empress. The Atrisian Emperors, including the 14th Atrisian Emperor, ruled Kitel Phard, and during the Imperial Era Empress Leeya governed the Regency Worlds.
Supreme Chancellor Sheev Palpatine, secretly the Sith Lord Darth Sidious, masterminded the Clone Wars and completed the Grand Plan of the Sith. He adopted the title of Galactic Emperor at the end of the war, transforming the Republic into the Galactic Empire. Following Sidious' death, the title of Galactic Emperor fell into disuse; not even the strandcast Snoke made an effort to claim it despite his role as Supreme Leader of the First Order.
Kylo Ren, grandson of Darth Vader, set out to conquer the galaxy as the First Order's new Supreme Leader. Sidious, having resurrected himself through cloning, offered to help Ren become the next Emperor. After Ren returned to the light side of the Force as Ben Solo, Sidious urged his granddaughter, the Jedi Padawan Rey, to give into the dark side and claim the Throne of the Sith as Empress. Ultimately, Sidious discarded the idea of a successor upon discovering the true nature of the Force-bond between Solo and Rey; they were a dyad in the Force. Although he succeeded in healing his cloned body with the dyad's power, Sidious' second destruction ended his dream of ruling a Sith Empire as an immortal Emperor.
- "Vengeful Waves"—Myths & Fables (In flashback(s))
- Star Wars: Episode III Revenge of the Sith
- Star Wars: Episode V The Empire Strikes Back (First appearance) (Appears in hologram)
- Star Wars: Episode VI Return of the Jedi
- Star Wars: Episode IX The Rise of Skywalker
- Star Wars: The Rise of Skywalker: Expanded Edition
- Star Wars: The Rise of Skywalker: A Junior Novel
- "Buyer Beware"—Dark Legends (Mentioned only) (In flashback(s))
- Star Wars: The Last Jedi: The Visual Dictionary (First mentioned)
- Dawn of Rebellion
- Star Wars: The Rise of Skywalker: The Visual Dictionary
- The Star Wars Book
- Star Wars: The Tiny Book of Sith